Steering device for industrial truck

ABSTRACT

A steering handle ( 1 ) of a truck is arranged over the battery box ( 2 ) of the truck. The steering handle ( 1 ) is journaled turnable in relation to an arm ( 3 ) around a journaling point ( 4 ), while the arm ( 3 ) in turn is journaled pivotable around a pivot point ( 5 ). By pivoting the arm laterally a position may be achieved where the handle is easily accessible from the side of the truck. The steering handle is pivotably arranged in the outer end of the arm in a pivot bearing that in turn is pivotable in the arm and parallel controlled in relation to the truck. Between the steering handle and the journal for the pivot movement detection means are arranged to detect the mutual turning that is then used to electronically/electrically turn the steered wheel of the truck.

[0001] Order picker trucks of low pick type are used in such a way that the operator picks goods into a container or put onto a pallet placed on the forks of the truck. This is done either by the driver standing on the floor next to the truck or on a special platform that is also used at the traveling, the truck being intended normally to be driven with the forks in the rear end that is with the driver facing away from the forks. Even if the platform of the truck is low this means a repeated stepping on and off the truck, sometimes perhaps for very short displacements. In order to facilitate the work it is known to arrange so called jogging buttons at the sides of the truck, by means of which the truck can be driven slowly forwards or backwards without any steering movement taking place. In this way the position of the truck can be adjusted in relation to for instance a load that is to be lifted on or off. Since however the truck can not be steered with less than that the operator steps up on the truck he must use corresponding time for this.

[0002] The object of the invention is to eliminate the above problem.

[0003] The above object is achieved with a steering means, that can be constituted by a steering handle, and that is made movable from at least one central position to one or in particular two lateral positions. In this way it becomes possible for the operator comfortably to use the steering means or handle when driving on the truck to and from the location as well as a more local moving where the operator can walk at the side of the truck and at the same time easily reach the steering means or handle that advantageously is located just inside the contour of the truck or extend insignificantly outside of this. Advantageously the steering means is arranged in the end of an arm that can be locked in the different positions. The steering means can be constituted by a more or less compact panel provided wit a small wheel with electronic or electrical transfer of the steering movements.

[0004] In an advantageous further development of the invention the steering means is a steering handle arranged in the outer end of an arm that can be swiveled around an axle located at the front edge of the platform, preferably at the center of this. In this way it becomes possible by allowing the arm to extend straight forward to place the handle at driving from the platform at a comfortable distance in front of the operator. By swiveling of the arm to either side the handle can be placed within comfortable reach even for a walking operator.

[0005] Generally on trucks like these the batteries are arranged directly in front of the platform of the driver for ergonomic reasons so that the operator is closest to the load that is behind the operator (at driving) on the forks and to secure in all positions that a large weight lies on the steering and driving wheel of the truck. By in accordance with a further development of the inventive thought arrange the pivot bearing of the arm at the front edge of the platform behind the battery and further pivotable rearwards it will be possible to pivot away the handle to such an extent in relation to the battery box that this can become freely accessible from above facilitating maintenance and exchange of battery.

[0006] In an advantageous further development of the invention the pivoting of the arm is coupled to a turning of the steering means or handle or its (zero-position) so that the steering means or handle in all positions of the arm has the same direction or the same direction in relation to the longitudinal direction of the truck independent of the pivoting of the arm. In this way the instinctive steering of the operator is facilitated at the same time as the repositionings are made easier. In the case with a steering handle the direction of the handle in relation to the longitudinal direction of the truck coinciding with or corresponding to the direction of the steering wheel in relation to the longitudinal direction of the truck.

[0007] This coupling of the movements of the arm and the steering means or the handle may advantageously be achieved by a first gear or cog-wheel being arranged rigidly connected with the steering means or journal of a steering handle and that over this cog-wheel runs a cog belt that also runs over a second cog-wheel located concentrically with the bearing of the arm and which second cog-wheel is non-turnable connected to the truck while the steering movement is transferred from the steering handle to the steered wheel in an electronic way with for instance a sensor in the handle.

[0008] At the pivoting of the arm the cog belt together with the cog wheels will serve as a parallelogram control, that is with cogwheels of the same size in both places a parallel movement of the steering means or handle is achieved without any further means being required and the handle will entirely automatic at driving straight forward also be directed straight forward independent of the pivot position of the arm.

[0009] Alternatively the cog wheel that is connected to the truck may instead be arranged in the upper end of a steering rod that is then directly or via for instance cog wheels and cog belts transfer the movement to the steered driving wheel of the truck. Also here a parallel control of the steering means or handle is achieved with simple and low cost mechanical components, which not only result in a very great reliability but also prevents the device from being cost increasing for the truck which is unwanted since this type of truck is comparatively cost sensitive.

[0010] The arm can be journaled in the upper end of a post fastened to the floor of the truck platform. This is in particular of advantage at tucks with a platform that is moveable in the height direction where in this way the steering means or handle follow the vertical movement.

[0011] In order to lock the arm and thereby the handle in the different positions a lock is arranged that can be freed with a button arranged in the handle.

[0012] Further advantages and characteristics of the invention are apparent from the subclaim and the following description of an embodiment shown in the enclosed drawings. FIGS. 1-3 show different handle positions for a truck according to the invention, while FIG. 4 show arm and handle in a longitudinal section and FIG. 5 a detail in a vertical cross section.

[0013]FIG. 1 schematically shows how a steering handle 1 for a truck is arranged centrally over the battery box 2 of the truck. The steering handle is journaled turnable in relation to an arm 3 around a journal point 4, while the arm in turn is journaled pivotable around a pivot point 5. By pivoting the arm laterally the position shown in FIG. 2 can be achieved. In a similar way the arm can be pivoted to the other side of the truck.

[0014] In FIG. 3 is shown how the arm by being pivoted further from the lateral steering positioning FIG. 2 place the steering handle in a service position behind the battery box that thereby will be accessible from above.

[0015] The steering handle is in FIG. 1 shown in a position corresponding to a steering straight forward and steering is achieved by turning of the handle. When pivoting the arm between the different positions the steering handle is always transferred with its present steering angle, which is achieved by a mechanical device described below in greater detail with reference to FIG. 4.

[0016] The arm 3 is in its pivot end provided with a downwards protruding bushing 7 that is swivably arranged on a tube-shaped vertical axle 6 that in turn via brackets 8 is arranged in a vertical rectangular beam or pillar 9 located centrally behind and next to the battery box 2. The beam 9 is connected to the platform floor of the truck and can on correspondingly equipped trucks follow the movements up and down of the platform floor.

[0017] The tube-shaped axle 6 extends upwards into the inner of the arm 3, where a cog wheel 10 is non-turnably fastened to the axle 6. Over the cogwheel a cog belt 10 runs with its parts extending to the other end of the arm.

[0018] In the other end of the arm a tube shaped vertical axle 14 is fastened to the bottom side of the arm 3 and essentially arranged inside the arm 3. A bushing 13 journaled on the axle 14 is on the upper side fastened to a plate 15, in one end of which the handle 1 is pivotably journaled moveable in a vertical plane via a hinge-joint 15. The handle 1 is in this manner turnably journaled relative the arm. On the outside of the bushing a cog wheel 12 is swivably journaled and the cog belt 11 runs over this cog wheel. In this way the cog wheels 10 and 12 will together with the cog belt constitute a parallel control for the cog wheel 12 that will thus always have the same diameter parallel to the length axis of the truck. By arranging between the cog wheel and the bushing coupled to the handle an angle sensor, for instance in the shape of a potentiometer or an optical detection of teeth on a wheel the steering movement or angle of the handle can be obtained and then by means of suitable servo means be transferred to the steered wheel of the truck.

[0019] The cog wheel 10 is provided with recesses 17 on the circumference. These recesses correspond to the positions in which one wish to use the handle and a lock 18 in the arm 3 can snap into these recesses. The lock 18 is by a spring biased towards the locking position and can by a wire 19 be freed from the respective locking position to allow the pivoting of the arm. The wire runs from the lock to an actuation means 20 in the handle. The wire runs through the tube-shaped axle 14 and does therefor not interfere with the turning of the handle at steering.

[0020] Also leads from the controls in the handle pass through the tube-shaped axle 14 as well as through the tube-shaped axle 6.

[0021] Since the center of the turning movement of the handle lies a distance in front of the grip a tiller arm feeling is obtained in the steering which facilitates intuitive steering. 

1. Steering device for truck, characterized in that a control means is arranged moveable between a centered middle position for use when the driver stands on the platform of the truck and at least one outer position in which the truck can be controlled from the side and the handle is at the side of the truck inside the contour of this or more or less outside of this.
 2. Device according to claim 1, characterized in that the control means of the truck is arranged in the outer end of an arm arranged centrally in the truck and that the arm is pivotable.
 3. Device according to claim 1 or 2, characterized in that a lock device is arranged in particular controllable from the steering means to lock and free respectively the pivoting movement of the arm so that defined work positions are established for the control means.
 4. Device according to any of the preceding claims, characterized in that the center of the pivot movement is above the front edge of the platform.
 5. Device according to any of the preceding claims, characterized in that the pivot movement of the arm is transferred via cog wheels and a cog belt to a holder for the steering means in the arm so that the direction of the steering means is uninfluenced by the pivoting of the arm.
 6. Device according to any of the preceding claims, characterized in that the steering means is a handle which is turned in its entirety at steering.
 7. Device according to claim 6, characterized in that the center of turning for the handle in the outer end of the arm coincide with the steering movement of the handle.
 8. Device according to any of the preceding claims, characterized in that the turning movement of the steering handle in relation to the cog wheel concentric with the turning center of the steering handle is sensed electronically, then to be used for the steering of the truck.
 9. Device according to claim 7, characterized in that the pivot point of the handle is situated a short distance in front of the grips of the handle so that a certain tiller arm feel is achieved.
 10. Device according to any of the preceding claims, characterized in that the arm is journaled in the upper end of a pillar that in turn is fastened to a platform for the operator. 